The Co-benefits of Domestic and Foreign GHG Mitigation on US Air Quality

• Quantify the total co-benefits for air quality in the US from global GHG mitigation, at fine resolution. • Separate the co-benefits from domestic GHG mitigation from those from foreign mitigation. • Separate the co-benefits of air quality into contributions from co-emitted air pollutants and changes via future climate change Approach • We use scenarios from the GCAM global energy economics model – a Reference Case (REF) and RCP4.5. RCP4.5 differs from REF only in the application of a climate policy. Therefore, we simulate directly the effects of global GHG mitigation on co-emitted air pollutants. • We use WRF to downscale the global meteorology for these future scenarios from the GFDL general circulation model (AM3) simulations of RCP8.5 (with similar forcing as REF) and RCP4.5. We use the spectral nudging technique to keep the WRF performance consistent with the GCM. • SMOKE is used to process the global RCP emission dataset to the regional US domain. We will lead the role in directly processing IPCC emissions into regional CONUS domain instead of using the emissions scales of IPCC and NEI dataset, which is not robust and less accurate. • We also create dynamical boundary conditions (BCs) from our global MOZART-4 simulation for future CMAQ runs. • CMAQ model v5.0.1 with new isoprene mechanisms will be used for multi-year simulations at 36km resolution, for different scenarios using input files above.